Sunday, April 15, 2012

Simple antennas for the Hawaii Island Amateur Radio Operator--a continuing series

Have you ever thought of installing a small, portable HF rig and collapsable antenna in your vehicle for impromptu or emergency operations?  During the past week, wet weather and sometimes marginal road conditions got me thinking about what HF radio system I would use should a traffic emergency arise where I couldn't get home or where cell phone coverage would be unusable.  Along the Hamakua Coast of Hawaii Island, cell phone coverage is spotty and there are many areas inadequately served by this handy communications device.  Geography plays a big role in limiting cell phone coverage, with mountain peaks and ridges often degrade the signal available.

So, last week I decided to make a small upgrade in my mobile capability with the creation of a small, easily portable HF system to complement my bare-bones 2-meter capability (HT with mag-mount antenna on the rood of my van).  I selected my old, trustworthy Yaesu FT-7 (10 watts output), a large marine, deep cycle battery in the garage, and a B & W window ledge apartment antenna for the HF system.  I acquired the B & W antenna back in the mid-80s and have used it a few times for impromptu operations at the qth or at the nearest public park bench.  MFJ markets a close relative of the old B & W known as the MFJ-1622, complete with an air wound loading coil, telescoping 5 1/2-foot radiator, choke balun, counterpoise wire, a length of RG-58 coax, and a safety rope.  All of these components take up little room in the van and can be stored in a large plastic tub behind the passenger seats.

This weekend I tried out my older version of the MFJ system and it worked well enough on 40 and 20 meters to make this part of my emergency mobile and qth standby station.  Other than the cost of the original B & W apartment antenna, I was out very little.  The MFJ -1622 costs $99.95 in the MFJ 2012 Ham Catalog.  MFJ has a few other portable antennas you may want to consider for standby use.  My emergency mobile HF works and will be kept in the van for general operating or for emergency use.

If you don't have a standby rig for emergency uses, you may want to consider the ICOM-703, SGC-2020, any rig from the Elecraft series, or even Yaesu and Kenwood rigs that were designed for qrp use.  Power can be supplied from a golf cart battery, a trowling fishing battery, or any other deep-cycle battery.  Vehicle batteries can be used, but they weren't designed for this purpose and performance may vary.  The only thing I'm lacking now is a compact solar cell array to keep the deep cycle battery charged.  Presently, I operate from the deep cycle battery about once a week and keep the system charged with a trickle charger.  My main station uses a deep cycle marine battery and I keep that charged on a trickle charger as well.  The old Swan 100 MX can run for a day or two at qrp levels (10 watts SSB or CW) before voltage drops below 13 volts.  Of course, your mileage may vary, depending on the type of rig and power level you use.  Some of the earlier Ten-Tec rigs, such as the 509, century 21, or even the Argosy I, II can be pressed into service.  There are several low power Heathkit transceivers such as the HW-7, HW-8, and HW-9 that can be used if cw is your preferred mode of operation.  For the do-it-yourself enthusiast, there are many good kits available in a variety of configurations.

The important thing is to have a backup rig in case your main rig is down or you lose power at your qth.  I've also stashed a 100-foot spool of #22 gauge wire, insulators, small tools, connectors, and 50-feet of RG-6 coax (with connectors) in the emergency tub containing the HF station.  All of these items fit neatly in the back of my van.

One never knows what will happen these days and an emergency HF/VHF station in your vehicle could save your life some day.

Have a good weekend!

Aloha es 73 de KH6JRM--BK29jx15